Many home care and personal care formulations seek to deliver benefit agents to substrates such as textiles, hard surfaces, hair and skin. Encapsulation of the benefit agent in particles has been proposed as a means of enhancing delivery. Encapsulation of perfumes has generated particular interest and activity in recent years.
Leakage of the benefit agent from the encapsulating particle over time is a known problem with many encapsulates. Leakage into the formulation into which the encapsulate particle has been incorporated leads to instability problems as well as performance issues. Performance issues include not only loss of perfume intensity but also loss of timing of perfume delivery.
Encapsulates comprising polyamides are known in the art.
WO 12/085864 (P&G) Discloses a population of encapsulates, the encapsulates comprising a shell and a core, said shell comprising a polyamide polymer that forms a wall that encapsulates said core, said core comprising a perfume composition. The perfume composition comprises perfume raw materials having a C log P of from 2 to 4.5; the encapsulate has a diameter of from 1 to 100 microns and a fracture strength of from 0.1 to 5 MPa.
U.S. Pat. No. 4,145,184 (P&G) Discloses a laundry detergent composition comprising, a laundry detergent composition comprising: (a) from 2 to 95 percent of a surfactant selected from the group consisting of anionic, nonionic, ampholytic and zwitterionic surfactants, and mixtures thereof; and (b) an effective amount of a perfuming agent comprising a perfume encapsulated in water insoluble, friable microcapsules having an average size of from 5 to 300 microns. The microcapsules have a shell wall material of polyamide.
WO 09/047745 (P&G) Discloses a composition comprising an encapsulate comprising a core comprising a benefit agent and a shell that at least encapsulates said core, said encapsulate further comprising a density balancing agent, said composition being a consumer product. The encapsulate's benefit agent is selected from perfume and shell comprises polyamides.
WO 11/056904 (P&G) Discloses an encapsulate comprising a) a core, comprising perfume and b) shell comprising polyamides.
Melamine formaldehyde capsules are known but, disadvantageously, need to be used in conjunction with a formaldehyde scavenger.
US 2008 146478 (International Flavors and Fragrances Inc) discloses a microcapsule comprising an active material, a nanoscaled material and an encapsulating polymer. The encapsulating polymer is selected from the group consisting of a vinyl polymer, an acrylate polymer, an acrylate acrylamide copolymer, melamine-formaldehyde polymer, urea-formaldehyde polymer and mixtures thereof to form a polymer encapsulated fragrance. See Claims 1, 2 and sections [0111] and [0113]
US 2004 071742 (International Flavors and Fragrances Inc) discloses a composition comprising: a fragrance material; said fragrance material encapsulated by a polymer to provide a polymer encapsulated fragrance; the polymer encapsulated fragrance is further coated by a cationic polymer.
US 2004 072719 (International Flavors and Fragrances Inc) discloses a composition comprising: a fragrance material; said fragrance material encapsulated by a polymer to provide a polymer encapsulated fragrance; the polymer encapsulated fragrance is further coated by a polyamine polymer.
U.S. Pat. No. 5,460,817 (Allied Colloids Ltd) discloses a particulate composition comprising particles having an anhydrous core comprising (a) a solid matrix polymer and an active ingredient distributed throughout the solid matrix polymer and (b) an outer protective coacervated polymer shell. The outer shell is formed of a cross-linked polymer (Polyvinyl alcohol).
WO 92/06672 (Revlon Inc.) Discloses a microencapsulate comprising one or more antiperspirant salts encapsulated within a shell wall which is susceptible to osmotic, enzymatic, or electrolytic degradation, or degradation due to water solubility of the shell wall.
We have now determined that improved particles comprise an outer shell of crosslinked mPVOH, produced with a crosslinking agent comprising a mixture of dextrans having different molecular weights, and an inner shell which comprises a polyamide (which comprises an aromatic group) and a core comprising a perfume. Use of the particles of the invention results in marked improvement in deposition efficiency and a corresponding consumer perceivable increase in benefit delivery.
Advantageously, the new capsules incorporate materials that are made substantially from renewable feedstocks, which helps to reduce environmental impact.